1. Field of the Invention
The invention relates generally to a differential mechanism, which transmits rotating power to the wheels of a motor vehicle.
2. Description of the Prior Art
A locker clutch can be used in a differential mechanism to secure one of the side gears and its axle shaft against rotation relative to the differential carrier, thereby enhancing traction of the driven wheels that are supplied with power through the differential.
When actuated, an electronic locking differential (ELD) mechanically connects a side gear to the differential case using an electrically-controlled lock mechanism, typically a dog clutch.
When the clutch is engaged, the electronic locking differential prevents relative speed differentials across the controlled wheels and transmits full engine combustion torque amplified by the transmission and axles torque ratios and reduced by efficiency and rotational losses, to the controlled wheels.
With the electronic locking differential engaged the maximum axle/transaxle input torque (AIT) is limited to the combined skid torque of the controlled wheels.
With the electronic locking differential engaged while cornering the torque across the differential is the delta between the left and right axle shaft torque and bound by the engaged dog clutch. The torque delta is a function of coefficient of friction surface, tire surface area turning radius and maximum gross vehicle weight.
A need exists for a control strategy that detects when the lock mechanism of an ELD is torque bound due to control wheel differential speed and enables rapid controlled disengagement of the lock mechanism when the differential speed across the controlled wheels decreases below a calibrated reference speed by applying the brakes.